Negative Pressure Dressings (PICOTM) on Laparotomy Wounds Do Not Reduce Risk of Surgical Site Infection

Negative Pressure Wound Therapy in Closed Colorectal Surgical Incisions: A Systematic Review and Meta-Analysis

The utilization of negative pressure wound therapy (NPWT) in lowering the incidence of infections in closed colorectal surgical incisions has not been thoroughly established, and recent trials have had conflicting results. This meta-analysis was conducted to synthesize the findings of available trial data and carefully evaluate the effectiveness of this intervention in colorectal surgery. The databases PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were combed for randomized controlled trials (RCTs) that compared negative pressure wound therapy to standard dressing in closed wounds of patients undergoing colorectal surgery. The incidence of surgical site infections (SSIs) was the primary outcome. Secondary outcomes included the occurrence of seroma and hematoma. The trial results were represented as odds ratios (OR) with a 95% confidence interval (CI), and a fixed-effects model was used. Nine studies found eligible were included, and the pooled results revealed that negative pressure wound therapy significantly reduced the incidence of surgical site infections (OR: 0.70; 95% CI: 0.53, 0.93; P= 0.02). Furthermore, there was a significant reduction in seroma (OR: 0.27; 95% CI: 0.08, 0.95; P = 0.04) and hematoma (OR: 0.20; 95% CI: 0.04, 0.96; P = 0.04). The use of negative pressure wound therapy for primarily closed incisions has been increasing, and our results indicate that it is superior to standard surgical dressings in preventing surgical site infections and other wound complications in colorectal surgeries.

Incisional negative pressure wound therapy for the prevention of surgical site infection: an up-to-date meta-analysis and trial sequential analysis

Background

The evidence on prophylactic use of negative pressure wound therapy on primary closed incisional wounds (iNPWT) for the prevention of surgical site infections (SSI) is confusing and ambiguous. Implementation in daily practice is impaired by inconsistent recommendations in current international guidelines and published meta-analyses. More recently, multiple new randomised controlled trials (RCTs) have been published. We aimed to provide an overview of all meta-analyses and their characteristics; to conduct a new and up-to-date systematic review and meta-analysis and Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment; and to explore the additive value of new RCTs with a trial sequential analysis (TSA).

Methods

PubMed, Embase and Cochrane CENTRAL databases were searched from database inception to October 24, 2022. We identified existing meta-analyses covering all surgical specialties and RCTs studying the effect of iNPWT compared with standard dressings in all types of surgery on the incidence of SSI, wound dehiscence, reoperation, seroma, hematoma, mortality, readmission rate, skin blistering, skin necrosis, pain, and adverse effects of the intervention. We calculated relative risks (RR) with corresponding 95% confidence intervals (CI) using a Mantel-Haenszel random-effects model. We assessed publication bias with a comparison-adjusted funnel plot. TSA was used to assess the risk of random error. The certainty of evidence was evaluated using the Cochrane Risk of Bias-2 (RoB2) tool and GRADE approach. This study is registered with PROSPERO, CRD42022312995.

Findings

We identified eight previously published general meta-analyses investigating iNPWT and compared their results to present meta-analysis. For the updated systematic review, 57 RCTs with 13,744 patients were included in the quantitative analysis for SSI, yielding a RR of 0.67 (95% CI: 0.59-0.76, I2 = 21%) for iNPWT compared with standard dressing. Certainty of evidence was high. Compared with previous meta-analyses, the RR stabilised, and the confidence interval narrowed. In the TSA, the cumulative Z-curve crossed the trial sequential monitoring boundary for benefit, confirming the robustness of the summary effect estimate from the meta-analysis.

Interpretation

In this up-to-date meta-analysis, GRADE assessment shows high-certainty evidence that iNPWT is effective in reducing SSI, and uncertainty is less than in previous meta-analyses. TSA indicated that further trials are unlikely to change the effect estimate for the outcome SSI; therefore, if future research is to be conducted on iNPWT, it is crucial to consider what the findings will contribute to the existing robust evidence.

Funding

Dutch Association for Quality Funds Medical Specialists.

Effectiveness of 3-Day Prophylactic Negative Pressure Wound Therapy on Closed Abdominal Incisions in the Prevention of Wound Complications: A Randomized Controlled Trial

OBJECTIVE

To determine the impact of negative pressure wound therapy of closed abdominal incisions on wound complications.

BACKGROUND

Surgical wound complications including surgical site infection complicating open abdominal operations are a burden on the economy. The outcomes of SSI include prolonged hospital stays, adjuvant treatment delay, and incisional hernias leading to a decrease in the quality of life. Prophylactic negative pressure wound therapy has recently been tried with promising results.

METHODS

A randomized controlled trial involving 140 patients post-laparotomy with primary wound closure was divided into 2 groups (70 patients each). For the first group, NPWT dressings were applied for the first 3 days and then conventional dressings for 4 days after. For the second group, conventional dressings were applied for 7 days. Patients were followed up for SSI, seroma, wound dehiscence, and hospital stay.

RESULTS

pNPWT was associated with a significantly lower rate of SSI development compared with gauze dressings (3/70 vs. 17/70) (p = 0.001). It also had a significant effect on lowering the incidence of seroma (0/70 vs. 7/70) (p = 0.007) and delayed wound healing (0/70 vs. 8/70) (p = 0.006) and on decreasing days of hospital stay (2.2 ± 0.6 vs. 3.5 ± 1.8) (p <0.00001). No significant difference was observed with regard to hematoma (0/70 vs. 1/70) (p = 0.5) or wound dehiscence (0/70 vs. 2/70) (p = 0.5). No burst abdomens or NPWT complications were recorded in our study.

CONCLUSION

Three-day NPWT applied to primarily closed incisions is effective in reducing the incidence of SSI, seroma, and delayed wound healing in abdominal operations compared to conventional gauze dressings.

Does Prophylactic Negative-Pressure Wound Therapy Prevent Surgical Site Infection After Laparotomy? A Systematic Review and Meta-analysis of Randomized Controlled trials

BACKGROUND

Prophylactic negative-pressure wound therapy (pNPWT) may prevent surgical site infection (SSI) after laparotomy, but existing meta-analyses pooling only high-quality evidence have failed to confirm this effect. Recently, several randomized controlled trials (RCTs) have been published. We performed an updated systematic review and meta-analysis to determine if pNPWT reduces the incidence of SSI after laparotomy.

METHODS

MEDLINE, Embase, CENTRAL and Web of Science were searched on the 25.08.2021 for RCTs reporting on the incidence of SSI in patients who underwent laparotomy with and without pNPWT. The systematic review was compliant with the AMSTAR2 recommendation and registered into PROSPERO. Risk ratios (RR) for SSI in patients with pNPWT, and risk difference (RD) between control and pNPWT patients, were obtained using random effects models. Heterogeneity was quantified using the I² value, and investigated using subgroup analyses, funnel plots and bubble plots. Risk of bias of included RCTs was assessed using the RoB2 tool.

RESULTS

Eleven RCTs were included, representing 973 patients who received pNPWT and 970 patients who received standard wound dressing. Pooled RR and RD between patients with and without pNPWT were of, respectively, 0.665 (95% CI 0.49-0.91, I²: 38.7%, p = 0.0098) and -0.07 (95% CI -0.12 to -0.03, I²: 53.6%, p = 0.0018), therefore demonstrating that pNPWT decreases the incidence of SSI after laparotomy. Investigation of source of heterogeneity identified a potential small-study effect.

CONCLUSION

The protective effect of pNPWT against SSI after laparotomy is confirmed by high-quality pooled evidence.

Efficacy of Prophylactic Negative-Pressure Wound Therapy with Delayed Primary Closure for Contaminated Abdominal Wounds

Background. Prophylactic negative-pressure wound therapy (NPWT) to prevent surgical site infection (SSI) may be effective for severely contaminated wounds. We investigated the safety and efficacy of NPWT with delayed primary closure (DPC) for preventing SSI. Methods. For patients with contaminated and dirty/infected surgical wounds after an emergency laparotomy, the abdominal fascia was closed with antibacterial absorbent threads and the skin was left open. Negative pressure (−80 mmHg) was applied through the polyurethane foam, which was replaced on postoperative days 3 and 7. DPC was performed when sufficient granulation was observed. The duration and adverse events of NPWT, the development of SSI, and the postoperative hospital stay were retrospectively reviewed. Results. We analyzed the cases of patients with contaminated (n = 15) and dirty/infected wounds (n = 7). The median duration of NPWT was 7 days (range 5–11 days). NPWT was discontinued in one (4.5%) patient due to wound traction pain. SSI developed in seven patients (31.8%), with incisional SSI in one (4.5%) and organ/space SSI in six (27.3%). The median postoperative hospital stay was 17 days (range 7–91 days). There was no significant relationship between postoperative hospital stay and wound classification ( $P=0.17$ ) or type of SSI ( $P=0.07$ ). Conclusion. Prophylactic NPWT with DPC was feasible and may be particularly suitable for severely contaminated wounds, with a low incidence of incisional SSI.

Negative pressure wound therapy for surgical wounds healing by primary closure

BACKGROUND

Indications for the use of negative pressure wound therapy (NPWT) are broad and include prophylaxis for surgical site infections (SSIs). Existing evidence for the effectiveness of NPWT on postoperative wounds healing by primary closure remains uncertain.

OBJECTIVES

To assess the effects of NPWT for preventing SSI in wounds healing through primary closure, and to assess the cost-effectiveness of NPWT in wounds healing through primary closure.

SEARCH METHODS

In January 2021, we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries and references of included studies, systematic reviews and health technology reports. There were no restrictions on language, publication date or study setting.

SELECTION CRITERIA

We included trials if they allocated participants to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with another.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trials using predetermined inclusion criteria. We carried out data extraction, assessment using the Cochrane risk of bias tool, and quality assessment according to Grading of Recommendations, Assessment, Development and Evaluations methodology. Our primary outcomes were SSI, mortality, and wound dehiscence.

MAIN RESULTS

In this fourth update, we added 18 new randomised controlled trials (RCTs) and one new economic study, resulting in a total of 62 RCTs (13,340 included participants) and six economic studies. Studies evaluated NPWT in a wide range of surgeries, including orthopaedic, obstetric, vascular and general procedures. All studies compared NPWT with standard dressings. Most studies had unclear or high risk of bias for at least one key domain. Primary outcomes Eleven studies (6384 participants) which reported mortality were pooled. There is low-certainty evidence showing there may be a reduced risk of death after surgery for people treated with NPWT (0.84%) compared with standard dressings (1.17%) but there is uncertainty around this as confidence intervals include risk of benefits and harm; risk ratio (RR) 0.78 (95% CI 0.47 to 1.30; I² = 0%). Fifty-four studies reported SSI; 44 studies (11,403 participants) were pooled. There is moderate-certainty evidence that NPWT probably results in fewer SSIs (8.7% of participants) than treatment with standard dressings (11.75%) after surgery; RR 0.73 (95% CI 0.63 to 0.85; I² = 29%). Thirty studies reported wound dehiscence; 23 studies (8724 participants) were pooled. There is moderate-certainty evidence that there is probably little or no difference in dehiscence between people treated with NPWT (6.62%) and those treated with standard dressing (6.97%), although there is imprecision around the estimate that includes risk of benefit and harms; RR 0.97 (95% CI 0.82 to 1.16; I² = 4%). Evidence was downgraded for imprecision, risk of bias, or a combination of these. Secondary outcomes There is low-certainty evidence for the outcomes of reoperation and seroma; in each case, confidence intervals included both benefit and harm. There may be a reduced risk of reoperation favouring the standard dressing arm, but this was imprecise: RR 1.13 (95% CI 0.91 to 1.41; I² = 2%; 18 trials; 6272 participants). There may be a reduced risk of seroma for people treated with NPWT but this is imprecise: the RR was 0.82 (95% CI 0.65 to 1.05; I² = 0%; 15 trials; 5436 participants). For skin blisters, there is low-certainty evidence that people treated with NPWT may be more likely to develop skin blisters compared with those treated with standard dressing (RR 3.55; 95% CI 1.43 to 8.77; I² = 74%; 11 trials; 5015 participants). The effect of NPWT on haematoma is uncertain (RR 0.79; 95 % CI 0.48 to 1.30; I² = 0%; 17 trials; 5909 participants; very low-certainty evidence). There is low-certainty evidence of little to no difference in reported pain between groups. Pain was measured in different ways and most studies could not be pooled; this GRADE assessment is based on all fourteen trials reporting pain; the pooled RR for the proportion of participants who experienced pain was 1.52 (95% CI 0.20, 11.31; I² = 34%; two studies; 632 participants). Cost-effectiveness Six economic studies, based wholly or partially on trials in our review, assessed the cost-effectiveness of NPWT compared with standard care. They considered NPWT in five indications: caesarean sections in obese women; surgery for lower limb fracture; knee/hip arthroplasty; coronary artery bypass grafts; and vascular surgery with inguinal incisions. They calculated quality-adjusted life-years or an equivalent, and produced estimates of the treatments' relative cost-effectiveness. The reporting quality was good but the evidence certainty varied from moderate to very low. There is moderate-certainty evidence that NPWT in surgery for lower limb fracture was not cost-effective at any threshold of willingness-to-pay and that NPWT is probably cost-effective in obese women undergoing caesarean section. Other studies found low or very low-certainty evidence indicating that NPWT may be cost-effective for the indications assessed.

AUTHORS' CONCLUSIONS

People with primary closure of their surgical wound and treated prophylactically with NPWT following surgery probably experience fewer SSIs  than people treated with standard dressings but there is probably no difference in wound dehiscence (moderate-certainty evidence). There may be a reduced risk of death after surgery for people treated with NPWT compared with standard dressings but there is uncertainty around this as confidence intervals include risk of benefit and harm (low-certainty evidence). People treated with NPWT may experience more instances of skin blistering compared with standard dressing treatment (low-certainty evidence). There are no clear differences in other secondary outcomes where most evidence is low or very low-certainty. Assessments of cost-effectiveness of NPWT produced differing results in different indications. There is a large number of ongoing studies, the results of which may change the findings of this review. Decisions about use of NPWT should take into account surgical indication and setting and consider evidence for all outcomes.

Incisional negative pressure wound therapy for clean-contaminated wounds in abdominal surgery: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The role of incisional negative-pressure wound therapy (iNPWT) in preventing surgical site infections (SSIs) in clean-contaminated abdominal wounds is still controversial. This meta-analysis was performed to evaluate whether the use of iNPWT could reduce SSIs and other complications in clean-contaminated abdominal surgery.

METHODS

The authors searched PubMed, EMBASE, Cochrane library, and Web of Science from database inception to 23 January 2021 for randomized controlled trials (RCTs). They assessed the risk of bias using the Cochrane Collaboration risk of bias tool and conducted a meta-analysis using RevMan 5.4.

RESULTS

Eleven RCTs, including 4112 patients, were analyzed, of which 2057 were treated with iNPWT and 2055 with standard dressings. The SSI rates (OR = 0.76, 95% CI = 0.61-0.94, P = 0.01), in patients undergoing an iNPWT intervention were significantly lower than those in patients receiving standard dressings. There was no statistically significant difference between the rates of incision dehiscence, seroma, and readmission between groups.

CONCLUSIONS

Application of iNPWT for clean-contaminated wounds in abdominal surgery reduced SSI rates but showed similar rates of wound dehiscence, seroma, and readmission compared with standard dressings.

Prophylactic Use of Negative Pressure Therapy in General Abdominal Surgery: A Systematic Review and Meta-Analysis

Background: Surgical site infections (SSIs) represent an economic burden to healthcare systems. The use of negative pressure wound therapy (NPWT) for SSI prophylaxis remains uncertain. Methods: A systematic literature search was conducted in Medline/PubMed, CINAHL, and Web of Science for relevant studies. The primary outcome was the evaluation of the effectiveness of NPWT for prophylaxis of SSI rates in general abdominal surgery. Secondary outcomes were rates of seroma and wound dehiscence, length of hospital stay, and re-admission rates. The statistical analysis was performed with random effect models. Results: A total of 3,193 patients from 20 articles (six randomized controlled trials [RCT], three prospective, eight retrospective, and three ambispective studies) were analyzed. Negative pressure wound therapy was associated with decreased rate of SSIs compared with standard dressing in a pooled analysis of non-randomized studies and RCTs (0.57; 95% confidence interval [CI], -0.4 to 0.8; p < 0.001). This result, however, needs to be challenged because of a significant statistical heterogeneity of the included studies (I² = 71%; p < 0.01). A separate analysis of the six RCTs failed to confirm the superiority of NPWT (0.64; 95% CI, -0.4 to 1.04; p = 0.07), also disclosing significant heterogeneity. The analysis of secondary outcomes was only possible in combination of randomized and non-randomized studies because of incomplete datasets in RCTs. Re-admission rates were lower after NPWT and no difference was observed for the incidence of seroma, wound dehiscence, and length of hospital stay. Conclusions: Based on available evidence, the routine use of NPWT for SSI prophylaxis after laparotomy in general abdominal surgery cannot be generally recommended.

Prophylactic negative pressure wound therapy for closed laparotomy wounds: a systematic review and meta-analysis of randomised controlled trials

Surgical site infections are a common source of post-operative morbidity and contribute significantly to healthcare costs. Patients undergoing emergency laparotomy and/or bowel surgery are particularly at risk. Prophylactic negative pressure wound therapy (NPWT) has been shown to reduce wound infection. However, to date, there has been a lack of consensus around its use for closed laparotomy wounds. We conducted a systematic review of randomised controlled trials comparing the use of prophylactic negative pressure wound therapy with standard dressings for closed laparotomy incisions. The primary outcome was incidence of incisional surgical site infection (SSI) at 30 days post-operatively. Secondary outcomes included superficial and deep SSI, skin dehiscence, fascial dehiscence and length of stay. A total of 2182 publications were identified, of which, following review of titles, abstracts and full texts, five studies met the criteria for inclusion. Across these studies, 467 patients were randomised to NPWT and 464 to standard dressings. Overall SSI rate was 18.6% (n = 87/467) versus 23.9% (n = 111/464) in the NPWT and standard dressing groups, respectively (Odds ratio 0.71, 95% CI 0.52–0.99, p = 0.04*). Deep SSI incidence was the same in both groups (2.6%). Both skin dehiscence and fascial dehiscence were slightly higher in the standard dressing group ((4.2%, n = 11/263 versus 3.1% (n = 8/261) and (0.9% (n = 3/324) versus 0.6% (n = 2/323)), respectively. This study observed that NPWT reduces the overall SSI for closed laparotomy wounds. It supports data recommending the use of prophylactic NPWT dressings, especially in high-risk patients in both emergency and elective circumstances.